1. Field of the Invention
This invention relates to a novel method and apparatus for generating and pumping foam. More particularly, this invention relates to a novel apparatus for generating and pumping foam by drawing fluid, generally air, into an intake of a pump introducing one or more chemicals and a foam solution into the fluid while it is being pumped, generating foam by passing the foam solution through a series of bores in at least one of the pumping members, and subsequently discharging this foam at the pump outlet.
2. Description of the Prior Art
Generated foam has many uses. The foam may be used not only for fighting fires wherein a blanket of foam is placed over the fire, but also in such uses as treating foliage with a foam-like insecticide, removal of wallpaper and in bleaching, to name only a few. However, present methods and apparatus for generating and distributing foam are unsatisfactory.
The most common method and apparatus for generating and pumping foam is the type where a foam solution is flowed over a netlike screen. As a blower forces air through the screen, the foam solution expands into air bubbles forming foam. The foam is then discharged through a suitable flexible conduit to a discharge site. This has many disadvantages. Not only is the blower and associated apparatus large and bulky, but the distance the foam may be transported before it is discharged is very limited. In addition, there is little or no control over the amount and texture of foam formed, and the foam will not flow into the wind without being scattered and rendered ineffectual. These disadvantages make this type of foam generator particularly detrimental in a number of applications where foam is utilized. For example, in fighting fires, the size of the blower and the apparatus normally requires at least two men to transport the apparatus to a site where the foam is to be released. Since the foam may not be transported to any great extent from the point where it is originally generated, the men fighting the fire must carry the apparatus relatively close to it. Further, since the foam scatters easily with the wind, it is usually necessary to place the apparatus in a location which is favorable to the direction in which the wind is blowing in order to have proper coverage of foam, which is not always possible. Another example of an application of foam where present foam generators are unsatisfactory is in applying a foam pesticide to foliage. Since the wind easily scatters the foam, the pesticide frequently damages plants which are not to be treated, and the lack of control over the quantity of foam generated frequently wastes the pesticide as more than necessary is utilized. Thus, as can easily be seen, it is desirable to have a method and apparatus for pumping foam which would overcome these disadvantages. It would also be desirable to have a foam generator wherein a number of different types of chemicals or ingredients can be selectively metered into the pump whereby a foam is generated which has a preselected chemical make-up in predetermined amounts.